The stomach, appendix, jejunum, ileum, ascending colon, transverse colon, descending colon, liver and spleen are attached to the posterior part of the abdominal wall by mesenteries which carry blood vessels and lymphatics to and from these organs. The mesenteries also contain lymph nodes. The mesenteries vary in thickness, but all contain large amounts of fatty tissue and blood vessels which vary in size from 1.0 cm. in diameter down to less than 0.1 mm. in diameter. The greater omentum is a double fold of mesentery and it too carries large numbers of blood vessels of varying size, and the thickness of the greater omentum is quite variable from one patient to another.
There are stapling devices for closing the bronchus, pulmonary artery, pulmonary veins, for closure of the large or small intestine, for closure of the stomach or stapling of the stomach for morbid obesity, for end-to-end anastomosis of the intestines, for side-to-side anastomosis of the intestines and for individual ligation and for division of a blood vessel. In addition, there is a variety of occluding clips for blood vessels and skin staplers. Because of the fatty tissue and the variety of sizes of blood vessels present in the mesentery and the omentum, the available staplers are not satisfactory for stapling the mesentery and the omentum. The best stapler only ligates one vessel at a time and it commonly tears blood vessels in the vicinity of its use, requiring time-consuming repairs after ligation of the intended vessel.
U.S. Pat. Nos. 4,606,345 (Dorband et al), 3,252,643 (Strekopytov et al), 3,795,034 (Strekopytov et al), Roehr et al 4,715,520, Tremblay 3,958,738 and Judge 4,667,865 were cited against the parent applications.
The Dorband et al patent describes a stapler gun and a method for stapling two staggered rows of two-part fasteners for joining body tissue with two-part plastic fasteners which are believed to be more suitable for remaining in the patient as compared to stainless steel staples. The device is designed to provide two rows of fasteners, which fasteners may be made of biologically absorbable or non-absorbable polymeric materials. One part of the fastener comprises a U-shaped staple which has legs that are caused to penetrate the tissue. The other part of the fastener is placed on the other side of the tissue and used to engage the legs of the staple and interlock therewith. There is no disclosure of staggering any place other than the midpoint of the staples, nor is there any disclosure of variations in the size of the fasteners, nor is there any discussion of this arrangement being satisfactory for use with a patient's mesentery.
The Strekopytov (U.S. Pat. Nos. 3,252,643 and 3,795,034) teach an older type of device used for applying rows of staples. Neither of these patents make reference to any differences in sizes of the staples in any of the rows nor to any staggering other than at the midpoints of the staples.
The Roehr et al patent shows a stapler which applies three rows of staggered staples. This patent does not show staggering of staples at any other point than the midpoint and the staples in each row are identical in size to the staples in the other rows. There is no reference to any variation in the size of the staples.
Applicant's U.S. Pat. No. 4,848,637 issued on July 18, 1989, and the patent about to issue on allowed application Ser. No. 07/350,758, filed May 12, 1989 describe process, stapler and cartridge suitable for stapling the mesentery and the omentum using two, three or four rows of staples having different crown size in at least one row of staples as compared to the other row of staples, including an arrangement of staples in which the crown size of alternate staples in the same row differ from crown size of the staples in between said alternate staples. This effective arrangement is based on the fact that the staples having larger crowns also have longer prongs and the prongs having smaller crowns have shorter prongs. This is based on the fact that the prong size is determined by the requirement to reach halfway across the bottom of the crown and also to have enough additional length to form a loop under the crown. This loop serves a similar function as a stitch in a suture or ligation used to seal off the blood vessels after an incision has been made in human tissue. The larger the loop is to be the greater will the length of the prong be in excess of that required to reach one-half the length of the crown. With mesentery and omentum a combination of large loops and smaller loops is desired to seal off the flow of blood from the blood vessels severed by the incision. Advantageously each blood vessel and also some fatty tissue to squeeze the blood vessel shut is embraced by a loop of the staple.
When the crown sizes are the same in a number of rows of staples, as provided in commercially available cartridges of staples, the staples in one row are staggered with respect to the staples in the adjacent row or rows. The staggering in each case is effected by positioning the beginning end of the first staple in the second row of staples opposite the midpoint of the first staple of the first row of staples. This means that the midpoint of each of the staples in the second row of staples is opposite a gap between staples in the first row. It also means that the gaps between the staples in the second row are opposite the midpoint of adjacent staples in the first row. The midpoint of the staples is where the ends of the prongs on the underside of those staples come near to each other and in many cases leave a gap between each other and between the prong ends and the crown. In some cases particularly when long prongs are used, the grooves in the anvil have to be deeper with a sharper curvature at the bottom of the groove thereby often causing a curve at the end of the prong which causes a space between the prong ends in their final positions. These conditions mean that blood vessels which come in the gaps between staples in one row will not be encased in a loop in the adjacent row of staples. It also is possible that a blood vessel may be punctured by one or both of the prong ends for a staple or may be in a gap between prong ends and the crown, or even in the space between the upper curvature of the prong loops.